Re: [geodesic 00031] Re: Simple Machines and Tensegrity
Bob Burkhardt
significant effect, but as the frequency goes up, or the number of
members go up, removing one of them has less and less effect, at least
for domes and spheres. I have thought tensegrity might be suited for
designing suspensions, like in the chassis of a car, and perhaps they
can be thought of as chassis for living machines etc. Wasn't that what
Buckminster Fuller called his house, a living machine? It was our good
fortune that he helped get mechanical engineers interested in structures.
The only structure in my tensegrity menagerie at
http://bobwb.tripod.com/synergetics/tensegrity/index.html which seems to
exhibit redundancy is the bean bag. I am trying to pursue my definition
from Fuller's point of view, at least where he seems rational, and
including non-redundancy (no elements in reserve) would be a small
concession I think. I don't see a particular need for it except Fuller
likes the idea, and after all he did invent the word. For myself I
would prefer to just put redundancy into the list of parameters which
differentiate tensegrities, but perhaps it belongs in the list that
determines the boundaries of the definition -- a bean bag is not a
tensegrity until it is stuffed so full that all the fibers of the
container are tensed and it becomes comparable to a balloon. It is
something to seriously consider. Like that other boundary structure,
the deresonated dome.
Incorporating tensegrity into robots would help make them more resilient
and perhaps less lethal in an accident. It would make design trickier,
but designers seem like they must be ready for that transition. It's
the next step. That seems where Tristan Sterk is headed and the dynamic
tensegrity bunch.
Patrick, how about linking us into bit.listserv.geodesic? I think
mostly we would contribute to it rather than the other way around. The
last two messages have the subject "Chinese antique". Could be relevant
I suppose.
Bob
Phil Earnhardt wrote:
> On Sep 22, 2008, at 6:11 AM, Doug Milliken wrote:
>
>> On Sun, 21 Sep 2008 21:43:43 -0600 Phil Earnhardt
>> <ph...@FloatingBones.com > wrote:
>>
>>>
>>> A tensegrity icosahedron is decidedly nonredundant.
>>>
>>> On the other hand, our body's structural system has a marvelous amount
>>> of redundancy.
>>
>> .....
>>
>>> Your comment about redundancy is a bit of a non-sequitur to our
>>> discussion on Simple Machines. Redundancy is not a criteria for any of
>>> the six simple machines. Were you going to comment about anything else
>>> I said in the last message?
>>
>>
>> I was actually thinking that the lack of redundancy might be
>> incorporated into a definition of tensegrity.
>
>
> Fuller mentions the nonredundancy in 700.03 of Synergetics.
>
> There's an interesting question here: could a mechanical network of
> tensegrity structures be designed so that the network was redundant?
> On the failure of any part, could the network be re-balanced solely
> by altering the tension on the elements in the individual
> [remaining] tensegrity structures? I'd love to hear what Bob has to
> say about that.
>
>> You keep going on about biological systems, which are obviously your
>> specialty.
>
>
> Yes. My biggest reason for contemplating simple machines was to find
> a question that physicists and mechanical engineers could explore
> without getting bogged down in the details of biological systems.
>
> I also think that structural specialists can get up to speed rapidly
> by reading Myers's "Anatomy Trains" (16-page summary at
> http://tinyurl.com/at-summary ), Levin's Papers and DVD (at
> www.biotensegrity.com ), and working hands-on with Flemon's models
> (at http://tinyurl.com/toms-models ). If you get a model from Tom, I
> recommend the double-tensioned pelvis model. Anyone who has worked
> through parts of Synergetics knows how hard it is to do that without
> having 3-dimensional models in your hands.
>
>> These have properties that are not normally found in man-made
>> structures, such as the ability to self-repair.
>
>
> Besides the ability to self-repair, biological systems also have the
> ability to patch their structure on the fly to keep moving when they
> must.
>
> I believe that roboticists would benefit from using tensegrity in
> their design. As far as I've seen, Robots today are all hookean. Non-
> hookean designs have two decided advantages:
>
> 1. The inherent damping of non-hookean systems lowers wear-and-tear.
> 2. Motion in non-hookean systems is far more energy-efficient.
>
> After robots are designed with flowing and resilient movement, what
> will "robot" break dancers call their dancing?
>
> --phil
>
>
>
senorpescado
> For low-frequency tensegrities, removing one member can have a very
> significant effect, but as the frequency goes up, or the number of
> members go up, removing one of them has less and less effect, at least
> for domes and spheres. I have thought tensegrity might be suited for
> designing suspensions, like in the chassis of a car, and perhaps they
> can be thought of as chassis for living machines etc. Wasn't that what
> Buckminster Fuller called his house, a living machine? It was our good
> fortune that he helped get mechanical engineers interested in structures.
>
> > (athttp://tinyurl.com/toms-models). If you get a model from Tom, I
> > recommend the double-tensioned pelvis model. Anyone who has worked
> > through parts of Synergetics knows how hard it is to do that without
> > having 3-dimensional models in your hands.
>
> >> These have properties that are not normally found in man-made
> >> structures, such as the ability to self-repair.
>
> > Besides the ability to self-repair, biological systems also have the
> > ability to patch their structure on the fly to keep moving when they
> > must.
>
> > I believe that roboticists would benefit from using tensegrity in
> > their design. As far as I've seen, Robots today are all hookean. Non-
> > hookean designs have two decided advantages:
>
> > 1. The inherent damping of non-hookean systems lowers wear-and-tear.
> > 2. Motion in non-hookean systems is far more energy-efficient.
>
> > After robots are designed with flowing and resilient movement, what
> > will "robot" break dancers call their dancing?
>
>
> - Show quoted text -
great information, and just updated one week agon
thanks Bob, quite a fontana de informacion
Senor Pescado
tambien offshore fish holding structures
as now in Puerto Rico
and Belize